These gates can be punched by the world owner to open or close them. But Tomb Robbers can change their status for a player who pays them - open ones will shut, shut ones will open.
Adventure Tomb Gate price in Growtopia: sells for about 3/WL (median of 1 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: LLJX